Short Interpregnancy Interval Following a Multifetal Pregnancy: Maternal and Neonatal Outcomes

Objective: To evaluate the maternal and neonatal outcomes of women with short interpregnancy intervals (IPI < 6 months) following a multifetal pregnancy. Study design: A multicenter retrospective cohort study of women with an index multifetal delivery and a subsequent singleton gestation between 2005 and 2021. The obstetrical outcomes of pregnancies following short IPI (<6 months) were compared to those with an IPI of 18-48 months. Additional analyses were also conducted for the other IPI groups: 7-17 months, and longer than 49 months, while women with an IPI of 18-48 months served as the reference group. The primary outcome was preterm birth (<37 weeks) rate. Secondary outcomes were other adverse maternal and neonatal outcomes. Univariate and multiple logistic regression analyses were performed. Results: Overall, 2514 women had a primary multifetal delivery with a subsequent singleton gestation at our medical centers; 160 (6.4%) had a short IPI, and 1142 (45.4%) had an optimal IPI. Women with a singleton gestation following a short IPI were younger, with lower rates of previous cesarean and fertility treatments. Women in the short IPI group had significantly higher rates of preterm birth <37 weeks, anemia (Hb < 11 gr%) on admission to the delivery room, and placental abruption. Multivariable logistic regression analysis demonstrated that short IPI is associated with an increased risk for preterm birth (aOR 2.39, 95% CI 1.12-5.11, p = 0.03). Conclusion: Short IPI following a multifetal gestation is associated with an increased risk for preterm birth in subsequent singleton pregnancy.